Pneumatic railroad-signal



(No Model.) 2 Sheets-Sheet 1.

J. L. L. KNOX.

PNBUMATIG RAILROAD SIGNAL.

No. 323,428. Patented Aug. 4, 1885.

j; L mi;

kA PETERS. PflcXD-Llkhognphcr. Walhhglnn, D. C.

{No Model.) 2 Sheets-Sheet 2.

J. L. L. KNOX.

` PNBUMATIG RAILROAD SGNAL. No. 323,428. Patented Aug. 4, 1885.

A/Q a @if lUNiTnn STnTns lPnTnNT Ormes.

JOHN L. L. KNOX, OF ALLEGHENY, PENNSYLVANIA.

PNEUVIA'UC RAILROAD-SIGNAL.

PEGIFCATION forming part of Letters Patent No. 323,428, dated August 4, 1885.

Application filed May 5, 1885. (No model.)

To all whom it may concern:

Be it known that I, JOHN L. L. KNOX, a citizen of the United States, and a resident of Allegheny, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Pneumatic Railroad-Signals, of which the following is a full, clear, and exact description.

My invention relates to that class of signals in which when a train enters upon a section the danger-signal facing opposite the direction of movement at the rear of the section is exposed, and at the same time the dangersignal facing in the direction of movement at the front extremity of the section is also exposed, While the corresponding signals of the section over which the train has already passed are simultaneously concealed.

The objects ofthe invention are, first, to simplif and compact the pump and signalmoving apparatus; second, to dispense With branch pipes; third, to simplify the mechanism which Works the pumps, and at the saine time insure the return of said mechanism to normal position after each movement; and, i'ourth, to render the movement of the signals certain and uniform.

The invention consists in the hereinafterdescribed means for attaining said objects.

ln the drawings, Figure 1, Sheet 1, represents a top plan view of my invention, with signal-box removed; Fig. 2, Sheet 2, a side elevation of my invention; Fig. 3, Sheet 2, a plan view of the top of the pump, showing the ports; Fig. 4, Sheet 1, a longitudinal section ofsameon lineA B of Fig. 3; Fig. 5, Sheet 1, a transverse vertical section of same on line C D of Fig. il; Fig. 6, Sheet, 2, a horizontal section of the casing containing the valves and signal mechanism, Fig. 7, a detail top plan view of one of the suction-valves; Fig. S, a section of same on line G H of Fig. 7, showing the valve-locks, Fig. 9, a section of same on line l J of Fig. 7; Fig. 10, a detail top plan viewof one ofthe forcing or pressure valves; Fig. 11, a longitudinal median section of same ou line E F of Fig. Fig. 11, a side elevation of the locks of the forcing-valves; Fig. 12, a detail View of the reciprocating rod and bifurcated lever by which the valve-stops are operated; Fig. 13, a horizontal section ofthe signal-bof: on line K L of Fig. 2; Fig. 14, a detail vienT of the safety-valve; Fig. 15, a rear elevation of the tappet; Fig. 16, an edge view of same; Fig. 17, a front elevation of same.

Similar iignres of reference indicate corresponding parts throughout the different views.

l is the track-rail, supposably at the beginning of one section of the road.

Secured to the road-bed or ties in any suitable manner, and in close proximity to the rail, is a bed-plate, 2, to which is bolted t-he bearing 3 for one end of a shaft, 4. A second bed-plate, 5, carries the bearing 6 of the other extremity of said shaft, the latter being at right angles to rail 1.

Fixed to that end of shaft 4 which lies nearest the rail 1 is a tappet, 7, of ovoid outline, Whose top normally extends some distance above said rail. Said tappet 7 is out away upon the outer side beneath the top at 8, in order that, when depressed, it shall not come in contact with the iange of the rail.

Midway of shaft et is secured a cross-piece, 9, Whose extremities are fastened to links 10. The. latter are bolted to shackles, which embrace two ordinary elliptic springs, 11. The object of this construction is to force tappet 7 (and the pump mechanism) back to normal position after having been actuated by the wheel of a passing car.

Attached to the extremity of shaft 4 beyond bearing 6 is a crank-arm, 12, to which is Secured the pitman 13. The free extremity of said pitman is secured to the piston-rod 14. of the pump 15. The casing of said pump is U-shaped, and provided at the ends of the top plate with four ports, 15" 15c 15d. ports 15il and 15b are connected with the cham1 ber 16, and the ports 15c 15L in like manner communicate with chamber 17. 1Within said chambers work the wings or pistons 18 19, by which the signal is operated. The Walls of the chambers 16 17 may all be cast in a single piece.

The chambers 16 17 have cach an end and two sides at right angles, and the remaining end curved through a quadrant Whose radius is substantially identical with the length of the wings or pistons 1819. Said curvatures are diagonally opposite each other. The chamber 1G is somewhat larger than 17, in order` The that the shafts ofthe valve-locking arms may not interfere, as will be hereinafter more fully explained. The pistons 18 19 are mounted on vertical shafts 20 21, respectively. Stops 22, formed on the casting and within the paths of the pistons, limit the movement of the latter and prevent them from passing beyond the ends of the quarter-circle, hereinbefore described. The rotation of the pistons through a quarter-circle is sufcientto move the targets 23 24 the required distance to exhibit them through the openings 23 24 at danger,7 or conceal them, as the case may require.

At that part of each chamber-casing which corresponds to the ends of the paths of the pistons 18 19 are slight recesses 25, and at one extremity of each chamber is a small opening, 26, communicating with thc open air. The object of this construction is to prevent the pistons cushioning upon the confined air, and also to avoid the vibration or walobling7 of the target. The shafts 2O 2l pass upward to the signal-box 27, and have bearings in the top of it. Said box is elliptiealin shape and contains two rotating targets, 23 24, each of which is arc-shaped, (preferably one-third of a circle,) and covers kone of the openings 23 24 when given a quarter-revolution.

By constructing the box and target as described I insure the proper exhibition of the target when the signal is set for danger.77 The targets are mounted upon arms 29, which are secured to the shafts 20 21, so that any movement of the pistons 18 19 causes the targets to turn in the proper direction.

Attached to the main shaft 4 upon theinside of the bearing 6 is a crank-arm, 30,which operates a pitman, 31. Said pitxnan has its free extremity hinged to a rod, 32, which reciprocates in bearings secured to or made i11- tegral with the pump-casing. Said rodis provided with pins 33 34 on the side next the pump-casing.

35 36 are two rocking shafts, which extend transversely through the valve chambers. Outside of said chambers the rocking sha-ft 35 is provided willi a bifurcated lever, 35, whose legs 35 35 straddle the pin 33, and the shaft 36 is provided with a bifurcated lever, 36, whose legs 36b 36c straddle the pin 34. Within the valve-chamber the shafts 35 36 are each provided with two arms, 37 37, having friction-rollers journaled in their extremities. One of these arms upon each shaft is adapted, when vertical, to rest upon the extensions of and lock the suction-valves 38 39, and the other arm is adapted to rest upon the bodies of and lock the forcing-valves 40 41. The arms-operating the suction-valves and those operating the fbrcing-valves are arranged at an angle of forty-five degrees to each other, so that when a suction-valve is locked the corresponding forcing-valve will be fiee, and vice versa.

The suction-valves 38 39 are adapted to open downward, and their upper edges rest against seats formed upon the floor of the valve-chamber. Each of these valves is provided with an extension, 42, rising at an obtuse angle from the body of the valve and havving its upper side reduced to form the arc of a circle whose radius is equal to the length ofone of the locking-arms. Said extensions are preferably constructed to overbalance the body of the valves, but this is not absolutely essential. A light spring presses upon the extension of either suction -valve and serves to instantly close it after same has been opened. The forcing-valves 40 4l open upward, and also have seats formed upon the iioor ofthe valve-chamber. Said forcing-valves are in general shape and construction substantially similar to the suction-valves, except that they open upward and have the tops of their bodies (instead of the tops of the extensions) reduced to the arc of a circle. Beneath the extensions 44 are springs 45, which keep said valves normally closed. In the tops of the valve-chambers are safetyvalves 46, whose function is to allow for the escape of air when the latter has been too greatly compressed by the passage of a train of extraordinary length. The piston-head47 of the pump 15 is adapted to make but a halfstroke. In the side of the pump-casing are two openings, 48 49, which lie directly before and behind said head when the latter is at rest; but when the piston is reciprocated in either direction, one of said openings is covered by the body of the head. The object of this construction is to prevent retardation of movement of the piston-head bythe formation of a partial vacuum when the'pistou is in operation, and consequently to avoid air-cushioning of said head.

5() 50 is the main-line pipe, which in each signal apparatus enters chamber 16 upon one side and chamber17 upon the other side. Upon either side of the signal apparatus said mainline pipe is provided with an airchamber, 51. The object ot said air-chamber is to diffuse the pulsations caused by the strokes of the pump and render the pressure or exhaust in the pipes and connected apparatus more constant.

The operation of the invention is as follows:V .Vhen a train passes in the direction of the arrow 1, (see Fig. 2,) the front wheel ofthe engine strikes tappet 7 and throws it in the direction iu which said arrow points. The piston 14 and rod 32 are thereby simultaneously thrust forward. The effect of this action is to lock the forcing-valve 40 in chamber 16, free the suction-valve 38, lock the suction-valve 39, and free forcing-valve 41. The air from the pump is thereby forced into chamber 17 IOO IIO

and piston 19 started toward the position shown in Fig. 6. At the same time a portion of the air is forced through the main-line pipe at 50 to the chamber of the next signal apparatus ahead, corresponding to chamber 16, and tends to throwvits piston 18 and target 23 to danger.77 Wl hen the first wheel of the train has passed beyond the tappet 7 the springs ll draw the piston 14 (and tappet) back to normal position. The effect of this is to exhaust the air at thei'ight of the piston-head. As the suction-valve in chamber 17 is locked and the forcing-valve in said chamber opens upward, no air can be drawn from said chamber. On the other hand, the suction-valve in chamber 16 being free the air in said chamber is exhausted to a certain extent, and the air in the main-line pipe rushes in to fill the partial vacuum. Said pipe being connected with the corresponding chamber,17, of the signal apparatus placed at the end of the section in rear of train, and that signal having been left at danger,7 the tendency of the exhaust is to draw the wing 19 and target 24 of said rear signal out of sight, or at safety As each wheel ofthe train passes over thet appet 7, an additional quantity of air is forced into chamber 17 and an additional quantity withdrawn from chamber 16, andpiston 19 and its target 24 arebrought to dangein Piston19 and its target 24 of the signal apparatus in rear of train is brought to safety,77 and piston 1S and its target 23 of the signal apparatus at next section in front is set at dangeixi 1f a train pass along the track in the direction ofarrow 2, the rod 32 is thrown backward, carrying with it the legs 35b 36. This rocks shafts 35 36 in the opposite direction to that already described and reverses the action of the valvelocks. ln this case the forcing-valve 41 in chamber 17 is locked and the suction-valve freed, while the forcing-valve in chamber 16 is freed and the suction-valve locked. `The passage of the car-wheels over tappet 7 is thereby made to force air into chamber 16 and exhaust it from chamber 17. The effect of this would be to set target 23 to danger, set target 23 of apparatus in rear of train at safety,I7 set target 24 at safe-ty,77 and set target 24 of next apparatus ahead of train at danger. The movement of tappet 7 and connected mechanism, after the stroke of a wheel moving in a given direction, is not sufficient to reset the valves. 1f the valves are all unset, the relative position ot' the legs 35i 35 36c and pins 33 34 would be thus:

The movement of the 32 33 34 tappet 7 corresponding to a quarter-stroke of the piston, would throw pins 33 34 sufficiently forward to make the legs assume this position:

32 33 34 so as to lock the suctionvaive in one chamber and the forcing-valve in the other. On return-stroke, by action of springs 11 the pins 33 34 return to position tirst shown, while the legs and connected mechanism are at a stand still, thus:

2M 3 33 34: the movement of rod 32 corpositions to be thus: 32

l while on the return-stroke it will be thus:

33 34 ceived that the position ofthe legs, and consequently of the valve locks, can always be changed by the outstroke but never bythe instroke, the valves being always set by the first wheel which strikes the tappet in a given direction,and always remaining set until a wheel coming in an opposite direction strikes said tappet.

Having thus described my invention, what 1 claim is- 1. The combination, with the rotary shaft 4 and flanged rail 1, of the tappet extending above said rail, having the top 8 cutaway beneath said top, substantially as and for the purpose described.

2. The combination, with the shaft 4, of the cross-piece 9, links 10, and elliptic springs 11, arranged substantially as and for the purpose specified.

3. The combination ofthe pump-easing 15, the pistonn 14, adapted to make a quarterstroke when the tappet 7 is forced in either direction, the piston-head 47 of a thickness not less than the length of said quarter-stroke, and the orifices 48 49, formed in the pumpcasing directly in front and rear of said head 47 when the latter is in normal position, substantially as and for the purposes described.

4. The combination, with the pump, ofthe valve-chest, provided with chambers 16 17, containing suitable pistons for working the targets, the suction-valves 3S 39, and force- Valves 40 41, said suction -valves covering ports connecting, respectively, with opposite extremities of the pump, and said forcingvalves also covering ports connecting, respectively, with opposite extremities of thepump, substantially as described, whereby when the Thus it will be perbe exhausted from the remaining chamber, for the purpose set forth.

5. The combination, with the forcing and suction valves, of the rocking shafts 35 36, provided with bifurcated levers 35"36,adapt ed,when said shafts are simultaneously rocked in a given direction, to free a suction-valve and lock a forcing-valve in one chamber, while simultaneously locking a suction-valve and freeing a forcing-valve in the remaining chamber, as and for the purposes set forth.

6. The combination, with the valves and the rocking shafts provided with lockingarms and bifurcated levers, of the reciprocating bar 32, provided with pins 33 34, adapted to engage with the legs of said bifurcated lcvers, substantially as and for the purposes described.

7. The combination of the valve-chest proget-operating piston, a forcing and a suction valve, and a valve-locking device in each chamber, of a main-line pipe communicating at one end of the valve-chest directly with chamber 17, and at the other end of the chest air is forced into one of said chambers it will l IOO vided with chambers 16 17, and having a taring-arms 37 37, and bifureated levers 35n 36, reciprocating bar 32, and mechanism for opro erat'ing piston 14 and bar 32, substantially as and for the purposes described.

JNo. L. L. KNOX.

Witnesses:

NV. D. THOMAS, LENoX SIMPSON. 

